Photovoltaic air conditioner self-adaptive power adjusting strategy and photovoltaic air conditioner system

Abstract

The invention discloses a photovoltaic air conditioner self-adaptive power adjusting strategy and a photovoltaic air conditioner system. The self-adaptive power adjusting strategy comprises the steps that electrical parameters of the alternating current side of a photovoltaic air conditioner are detected; comparing the electrical parameter with a preset threshold parameter, and judging a threshold interval in which the electrical parameter is located; and the running state of the photovoltaic air conditioner is adjusted according to the threshold value interval where the electrical parameters are located. According to the invention, the photovoltaic power is released and kept at the optimal power point, so that the photovoltaic power generation energy of the photovoltaic module is fully utilized; the condition that the photovoltaic power output by the photovoltaic module is larger than the alternating current side power can be avoided, then the bus voltage is prevented from rising, bus overvoltage protection is not frequently triggered, the stability and reliability of operation of the photovoltaic air conditioner are improved, and the service life of a bus capacitor and other corresponding electronic elements is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a photovoltaic air conditioning adaptive power regulation strategy and a photovoltaic air conditioning system. Background Art

[0002] Existing photovoltaic air conditioners generally include a pure photovoltaic mode and a grid-connected power generation mode. When the photovoltaic air conditioner is in the pure photovoltaic mode, it completely relies on the electricity generated by the photovoltaic panels of the photovoltaic air conditioner and does not obtain any electricity from the power grid; when the photovoltaic air conditioner is in the grid-connected power generation mode, the photovoltaic air conditioner can not only use the electricity generated by the photovoltaic panels for power supply, but also feed back excess photovoltaic power to the power grid. At the same time, when the photovoltaic power is insufficient, it can obtain electricity from the power grid for power supply.

[0003] Under normal circumstances, photovoltaic air conditioners need to limit their current on the AC side to a certain value. In this case, the photovoltaic power needs to be limited in pure photovoltaic mode. The existing method is generally to directly limit the photovoltaic power to a specific value. However, this will cause the AC side current to drop below the limit current after the pure photovoltaic mode is switched to the grid-connected power generation mode. At this time, the photovoltaic power generation energy generated by the photovoltaic panel is not fully utilized, resulting in a waste of photovoltaic power generation energy. Moreover, when the AC side voltage drops, the power generation power of the photovoltaic panel is still maintained at a specific value. This will cause the power generation power of the photovoltaic panel to be greater than the AC side power, thereby raising the bus voltage and causing frequent triggering of the bus overvoltage protection. In severe cases, the bus capacitor will be damaged. Summary of the invention

[0004] The present invention provides a photovoltaic air-conditioning adaptive power regulation strategy and a photovoltaic air-conditioning system, which are used to solve the problem in the prior art that photovoltaic air-conditioning wastes photovoltaic power generation energy, raises the bus voltage to frequently trigger bus overvoltage protection, and in severe cases will cause damage to the bus capacitor.

[0005] The technical solution of the present invention is a photovoltaic air conditioner adaptive power regulation strategy, the adaptive power regulation strategy includes:

[0006] Detect electrical parameters on the AC side of photovoltaic air conditioners;

[0007] Comparing the electrical parameter with a preset threshold parameter, and determining the threshold interval in which the electrical parameter is located;

[0008] The operating state of the photovoltaic air conditioner is adjusted according to the threshold range of the electrical parameter.

[0009] Further, the electrical parameter includes a current Iac, the threshold parameter includes a first current limit value Imax1 and a first current limit value Imax2, and the first current limit value Imax1 is less than the first current limit value Imax2, and the adaptive power regulation strategy includes:

[0010] When Imax1≤Iac<Imax2, it is determined that the photovoltaic air conditioner maintains the current photovoltaic power;

[0011] When Iac≥Imax2, it is determined that the photovoltaic air conditioner reduces the photovoltaic power;

[0012] When Iac<Imax1, it is determined that the photovoltaic air conditioner performs photovoltaic optimization to keep the photovoltaic power at the optimal power point.

[0013] Furthermore, when Iac≥Imax1, the adaptive power adjustment strategy includes:

[0014] Acquire a maximum power limit value Ire of the photovoltaic power of the photovoltaic air conditioner, wherein the maximum power limit value Ire is not greater than the first current limit value Imax1;

[0015] Determining whether the current Iac is greater than the maximum power limit Ire;

[0016] If so, determining that the photovoltaic air conditioner performs photovoltaic optimization;

[0017] If not, it is determined that the photovoltaic air conditioner again compares the current Iac, the first current limit value Imax1 and the first current limit value Imax2.

[0018] Furthermore, when Iac<Imax1, the adaptive power adjustment strategy includes:

[0019] Obtaining an actual output power P of the photovoltaic module of the photovoltaic air conditioner and a first voltage Um corresponding to a maximum output power Pmax;

[0020] When the operating voltage U of the photovoltaic module is lower than the first voltage Um, the actual output power P is compared with a preset power limit reference value Plim of the photovoltaic module;

[0021] If P≥Plim, it is determined that the photovoltaic air conditioner stops photovoltaic optimization and maintains the current photovoltaic power;

[0022] If P<Plim, it is determined that the photovoltaic air conditioner continues to maintain photovoltaic optimization.

[0023] Furthermore, when P≥Plim, the adaptive power regulation strategy includes:

[0024] Obtaining a current duty cycle Dt and a limited duty cycle reference value Dlim of the photovoltaic air conditioner;

[0025] Determine whether the current duty cycle Dt is equal to the limit duty cycle reference value Dlim;

[0026] If so, determining that the photovoltaic air conditioner performs photovoltaic optimization;

[0027] If not, it is determined that the photovoltaic air conditioner continues to stop photovoltaic optimization and maintains the current photovoltaic power.

[0028] Furthermore, the calculation formula of the current duty cycle Dt is:

[0029] Dt=ΔD+D(t-1);

[0030] ΔD=K p ×e v +K i ×∫e v dt;

[0031] e v =Vref-Vout;

[0032] Among them, ΔD is the duty cycle disturbance step, D(t-1) is the duty cycle at the previous moment, K p is the proportional gain, K i is the integral gain, e v is the error signal, Vref is the preset voltage reference value of the bus, and Vout is the output voltage output to the bus.

[0033] Furthermore, the adaptive power regulation strategy includes:

[0034] Acquire a real-time measurement value AD_Iac, a first protection threshold value Iref1, and a second protection threshold value Iref2 output by the AC current sensor on the AC side;

[0035] Determine whether the real-time measurement value AD_Iac is in the interval (Iref1, Iref2);

[0036] If so, determining that the photovoltaic air conditioner keeps running;

[0037] If not, it is determined that the photovoltaic air conditioner triggers a protection mechanism and the photovoltaic air conditioner is in a completely power-off state.

[0038] The present invention also provides a photovoltaic air conditioning system, the photovoltaic air conditioning system comprising:

[0039] A bus bar, on which a bus bar capacitor unit and an air conditioner are connected in parallel;

[0040] Photovoltaic modules, which are used to convert solar energy into electrical energy;

[0041] A DCDC module, the DCDC module is connected to the photovoltaic module; the DCDC module is used to convert the direct current output by the photovoltaic module into direct current suitable for use by other electrical equipment;

[0042] An inverter module, the inverter module is connected to the DCDC module through a busbar, and the inverter module is also connected to the power grid; the inverter module is used to convert the direct current output by the DCDC module into alternating current to feed back to the power grid, or convert the alternating current output by the power grid into direct current to feed other electrical equipment;

[0043] A control module is used to obtain electrical parameters and compare them with preset threshold parameters, and adjust the operating state of the photovoltaic air conditioner according to the comparison result.

[0044] Furthermore, the photovoltaic air conditioning system also includes:

[0045] An AC current sensor is connected in series between the inverter module and the power grid;

[0046] A protection module, wherein the protection module is connected to the AC current sensor and the control module respectively; the control module is also used to cut off the power supply of the photovoltaic air-conditioning system according to the output of the protection module.

[0047] Furthermore, the photovoltaic air conditioning system also includes:

[0048] A direct current sensor connected in series between the photovoltaic module and the DCDC module;

[0049] A voltage sensor is connected in parallel between the photovoltaic module and the DCDC module.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] The present invention fully utilizes the photovoltaic power generation energy of the photovoltaic module by releasing the photovoltaic power and maintaining it at the optimal power point; it can also avoid the situation where the photovoltaic power output by the photovoltaic module is greater than the AC side power, thereby preventing the bus voltage from rising and not frequently triggering the bus overvoltage protection, thereby improving the stability and reliability of the photovoltaic air conditioner operation and extending the service life of the bus capacitor and other corresponding electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present invention; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0054] Figure 1 This is a first flow chart of the photovoltaic air conditioning adaptive power regulation strategy proposed by the present invention;

[0055] Figure 2 This is a second flow chart of the photovoltaic air conditioner adaptive power regulation strategy proposed by the present invention;

[0056] Figure 3 This is a third flow chart of the photovoltaic air conditioning adaptive power regulation strategy proposed by the present invention;

[0057] Figure 4 PU curve diagram of the photovoltaic module proposed in the present invention;

[0058] Figure 5 This is a module block diagram of the photovoltaic air conditioning system proposed by the present invention;

[0059] Figure 6 The circuit topology diagram of the photovoltaic air conditioning system proposed by the present invention;

[0060] Figure 7 This is a circuit topology diagram of the protection module proposed in the present invention.

[0061] Reference numerals:

[0062] 10. Bus capacitor unit;

[0063] 20. Air conditioner;

[0064] 30. Photovoltaic modules;

[0065] 40. DCDC module;

[0066] 50. Inverter module;

[0067] 60. Power grid;

[0068] 70. Control module;

[0069] 80. AC current sensor;

[0070] 90. Protection module;

[0071] 100. DC current sensor;

[0072] 110. Voltage sensor;

[0073] 120. Filter module. DETAILED DESCRIPTION

[0074] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described features. In addition, it should be noted that this specification describes many features. Although certain features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0075] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0076] Example 1

[0077] Refer to the attached Figure 5 The photovoltaic air conditioner (also referred to as a photovoltaic air conditioning system, the same as in the whole text) proposed in this embodiment includes:

[0078] A photovoltaic module 30, wherein the photovoltaic module 30 is used to convert solar energy into electrical energy;

[0079] A DCDC module 40, which is connected to the photovoltaic module 30 and is used to convert the DC power output by the photovoltaic module 30 into a DC voltage suitable for use by other electrical equipment (including the inverter module 50 and the air conditioner 20, the same throughout);

[0080] The inverter module 50 is connected to the DCDC module 40 via the bus BUS, and the inverter module 50 is also connected to the power grid 60; the inverter module 50 is used to convert the direct current output by the DCDC module 40 into alternating current to feed back to the power grid 60, or convert the alternating current output by the power grid 60 into direct current to feed to other electrical equipment;

[0081] The busbar BUS is also provided with a busbar capacitor unit 10 and an air conditioner 20 in parallel, and an AC current sensor 80 is connected in series between the inverter module 50 and the power grid 60 .

[0082] It should be noted that the photovoltaic air conditioner is also provided with a control module 70, and the control module 70 is respectively connected to the DCDC module 40, the AC current sensor 80 and other electrical equipment.

[0083] Among them, refer to the attached Figure 1 The present invention proposes a photovoltaic air conditioner adaptive power regulation strategy, the adaptive power regulation strategy includes:

[0084] The control module 70 obtains the electrical parameters of the AC side of the photovoltaic air conditioner through the AC current sensor 80, and the control module 70 is pre-set with threshold parameters;

[0085] The control module 70 compares the electrical parameter with a preset threshold parameter and determines the threshold interval in which the electrical parameter is located;

[0086] The operating state of the photovoltaic air conditioner is adjusted according to the threshold range of the electrical parameter.

[0087] It should be noted that the photovoltaic air conditioner proposed in this embodiment includes a pure photovoltaic mode and a grid-connected power generation mode, wherein the pure photovoltaic mode means that the photovoltaic air conditioner completely relies on the electric energy generated by the photovoltaic module 30 and does not obtain any electric energy from the power grid 60; while the grid-connected power generation mode means that the photovoltaic air conditioner can not only use the electric energy generated by the photovoltaic module 30 to power other electrical equipment, but also feed back excess photovoltaic electric energy to the power grid 60, and at the same time, when the photovoltaic electric energy is insufficient, it can obtain electric energy from the power grid 60 to power other electrical equipment.

[0088] It should be noted that the electrical parameters proposed in this embodiment include current Iac, the threshold parameters include a first current limit value Imax1 and a first current limit value Imax2, and the first current limit value Imax1 is less than the first current limit value Imax2; the current Iac, the first current limit value Imax1 and the first current limit value Imax2 proposed in this embodiment are all effective values ​​of alternating current.

[0089] In this way, when the photovoltaic air conditioner switches from the pure photovoltaic mode to the grid-connected power generation mode, the current Iac on the AC side will decrease. At this time, the control module 70 will compare the current Iac with the first current limit Imax1 and the first current limit Imax2, and according to the comparison result, the photovoltaic air conditioner needs to perform photovoltaic optimization, that is, the photovoltaic air conditioning system increases the connected DC load to release and maintain the photovoltaic power output by the photovoltaic module 30 at the optimal power point, thereby fully utilizing the photovoltaic power generation energy of the photovoltaic module 30; and it can also avoid the situation where the photovoltaic power output by the photovoltaic module 30 is greater than the AC side power, thereby preventing the bus voltage from rising, and will not frequently trigger the bus overvoltage protection, thereby improving the stability and reliability of the photovoltaic air conditioner operation, and extending the service life of the bus capacitor and other corresponding electronic components.

[0090] Further, based on comparing the electrical parameter with a preset threshold parameter, the adaptive power regulation strategy includes:

[0091] When Imax1≤Iac<Imax2, it is determined that the photovoltaic air conditioner maintains the current photovoltaic power, that is, the photovoltaic power of the photovoltaic air conditioner is limited;

[0092] When Iac≥Imax2, it is determined that the photovoltaic air conditioner reduces the photovoltaic power;

[0093] When Iac<Imax1, it is determined that the photovoltaic air conditioner performs photovoltaic optimization to keep the photovoltaic power at the optimal power point.

[0094] In this way, when the photovoltaic air conditioner switches from the pure photovoltaic mode to the grid-connected power generation mode, the current on the AC side of the photovoltaic air conditioner will decrease. If it is detected that Imax1≤Iac<Imax2 at this time, the control module 70 will maintain the current photovoltaic power, and will not keep the photovoltaic power output by the photovoltaic module 30 at the optimal power point. The control module 70 will display the mark position 2 on the screen of the host computer to which it is connected, to indicate that the control module 70 will limit the photovoltaic power at this time to maintain the current photovoltaic power; and if it is detected that Iac<Imax1, the control module 70 will make the photovoltaic module 30 perform photovoltaic optimization to keep the photovoltaic power at the optimal power point, thereby making full use of the photovoltaic power generation energy of the photovoltaic module 30; and it can also avoid the situation where the photovoltaic power output by the photovoltaic module 30 is greater than the AC side power, thereby preventing the bus voltage from rising, and will not frequently trigger the bus overvoltage protection, thereby improving the stability and reliability of the operation of the photovoltaic air conditioner, and extending the service life of the bus capacitor and other corresponding electronic components.

[0095] If it is detected that Iac≥Imax2, it indicates that the photovoltaic air conditioner switches from the grid-connected power generation mode to the pure photovoltaic mode. At this time, the current on the AC side of the photovoltaic air conditioner will increase, so the control module 70 will reduce the photovoltaic power output by the photovoltaic module 30, and the control module 70 will display the mark position 1 on the screen of the host computer to which it is connected, to indicate that the control module 70 will reduce the photovoltaic power output by the photovoltaic module 30 at this time; and when the photovoltaic power output by the photovoltaic module 30 is being reduced, the control module 70 will continuously and uninterruptedly compare the current Iac with the first current limit Imax1 and the first current limit Imax2 until it is detected that Imax1≤Iac<Imax2, at which time the control module 70 will maintain the current photovoltaic power and stop the photovoltaic optimization of the photovoltaic air conditioner, and the control module 70 will display the mark position on the screen of the host computer to which it is connected, which will switch from 2 to 1.

[0096] Furthermore, when Iac≥Imax1, that is, when the photovoltaic air conditioner does not need photovoltaic optimization, the adaptive power regulation strategy includes:

[0097] The control module 70 obtains the maximum power limit value Ire of the photovoltaic power of the photovoltaic air conditioner, and the maximum power limit value Ire is not greater than the first current limit value Imax1;

[0098] Determining whether the current Iac is greater than the maximum power limit Ire;

[0099] If so, determining that the photovoltaic air conditioner performs photovoltaic optimization;

[0100] If not, it is determined that the photovoltaic air conditioner again compares the current Iac, the first current limit value Imax1 and the first current limit value Imax2.

[0101] Therefore, when the control module 70 reduces or maintains the photovoltaic power, the photovoltaic power output by the photovoltaic module 30 will fluctuate. If the control module 70 detects that Iac>Ire, the control module 70 will execute the corresponding adjustment strategy according to the size between the current Iac and the first current limit Imax1 and the first current limit Imax2.

[0102] If the control module 70 detects that Iac≤Ire, the control module 70 will cancel or reset the currently set photovoltaic power limit flag, so that the photovoltaic air conditioner returns to normal photovoltaic optimization, that is, the control module 70 will display the flag position 0 on the screen of the host computer to which it is connected, so that the photovoltaic power continues to optimize towards the optimal point, so that the photovoltaic power remains at the optimal power point, until the photovoltaic power reaches the first current limit Imax1 and above, the photovoltaic air conditioner will stop photovoltaic optimization and maintain the current photovoltaic power. Compared with the method of directly limiting the photovoltaic power value in the prior art, this embodiment can make full use of the photovoltaic power generation energy of the photovoltaic module 30; and it can also avoid the situation where the photovoltaic power output of the photovoltaic module 30 is greater than the AC side power, thereby preventing the bus voltage from rising, and will not frequently trigger the bus overvoltage protection, thereby improving the stability and reliability of the photovoltaic air conditioner operation, and extending the service life of the bus capacitor and other corresponding electronic components.

[0103] Further, see Attachment Figure 2 and 4 When Iac<Imax1, that is, when the photovoltaic air conditioner needs photovoltaic optimization, the adaptive power regulation strategy includes:

[0104] The control module 70 obtains the actual output power P of the photovoltaic module 30 of the photovoltaic air conditioner and the first voltage Um corresponding to the maximum output power Pmax;

[0105] When the operating voltage U of the photovoltaic module 30 is lower than the first voltage Um, the actual output power P is compared with a preset power limit reference value Plim of the photovoltaic module 30;

[0106] If P≥Plim, it is determined that the photovoltaic air conditioner stops photovoltaic optimization and maintains the current photovoltaic power; that is, at this time, the control module 70 will reduce the operating voltage U of the photovoltaic module 30 to increase the current duty cycle Dt of the photovoltaic air conditioner.

[0107] If P<Plim, it is determined that the photovoltaic air conditioner continues to maintain photovoltaic optimization; that is, at this time, the control module 70 will increase the working voltage U of the photovoltaic module 30 to reduce the current duty cycle Dt of the photovoltaic air conditioner.

[0108] In this way, this embodiment limits or adjusts the photovoltaic power through the actual output power P of the photovoltaic module 30 to determine whether the photovoltaic air conditioner needs photovoltaic optimization.

[0109] Further, in order to ensure that the control module 70 can more accurately determine whether the photovoltaic air conditioner needs photovoltaic optimization, refer to the attached Figure 2 When P≥Plim, that is, when the photovoltaic air conditioner maintains the current photovoltaic power, the adaptive power regulation strategy includes:

[0110] The control module 70 obtains the current duty cycle Dt and the limited duty cycle reference value Dlim of the photovoltaic air conditioner;

[0111] Determine whether the current duty cycle Dt is equal to the limit duty cycle reference value Dlim;

[0112] If so, determining that the photovoltaic air conditioner performs photovoltaic optimization;

[0113] If not, it is determined that the photovoltaic air conditioner continues to stop photovoltaic optimization and maintains the current photovoltaic power.

[0114] Furthermore, the calculation formula of the current duty cycle Dt is:

[0115] D = ΔD + D(t-1);

[0116] ΔD=K p ×e v +K i ×∫e v dt;

[0117] e v =Vref-Vout;

[0118] Among them, ΔD is the duty cycle disturbance step, D(t-1) is the duty cycle at the previous moment, K p is the proportional gain, K i is the integral gain, e v is the error signal, Vref is the preset voltage reference value of the bus BUS, and Vout is the output voltage output to the bus BUS.

[0119] It should be noted that the duty cycle D(t-1) at the previous moment becomes the current duty cycle Dt after a PI adjustment cycle.

[0120] In this way, when the photovoltaic air conditioner maintains the current photovoltaic power, the control module 70 controls the switching time of the switching device in the DCDC module 40 through the current duty cycle Dt, thereby fully utilizing the photovoltaic power generation energy of the photovoltaic module 30; and it can also avoid the situation where the photovoltaic power output by the photovoltaic module 30 is greater than the AC side power, thereby preventing the bus voltage from rising, and will not frequently trigger the bus overvoltage protection, thereby improving the stability and reliability of the photovoltaic air conditioner operation, and extending the service life of the bus capacitor and other corresponding electronic components.

[0121] Furthermore, in order to further improve the stability and reliability of photovoltaic air conditioner operation and prevent photovoltaic air conditioner from being damaged due to overcurrent and other faults, refer to the attached Figure 3 , the adaptive power regulation strategy includes:

[0122] The control module 70 obtains the real-time measurement value AD_Iac, the first protection threshold value Iref1 and the second protection threshold value Iref2 output by the AC current sensor 80 on the AC side;

[0123] Determine whether the real-time measurement value AD_Iac is in the interval (Iref1, Iref2);

[0124] If so, determining that the photovoltaic air conditioner keeps running;

[0125] If not, it is determined that the photovoltaic air conditioner triggers a protection mechanism and the photovoltaic air conditioner is in a completely power-off state.

[0126] Example 2

[0127] Based on the same inventive concept, refer to the attached Figure 5-6 The present invention also proposes a photovoltaic air conditioning system, the photovoltaic air conditioning system comprising:

[0128] A bus bar BUS, on which a bus bar capacitor unit 10 and an air conditioner 20 are connected in parallel;

[0129] A photovoltaic module 30, wherein the photovoltaic module 30 is used to convert solar energy into electrical energy;

[0130] A DCDC module 40, the DCDC module 40 is connected to the photovoltaic module 30; the DCDC module 40 is used to convert the direct current output by the photovoltaic module 30 into direct current suitable for use by other electrical equipment;

[0131] An inverter module 50, the inverter module 50 is connected to the DCDC module 40 via a bus BUS, and the inverter module 50 is also connected to the power grid 60; the inverter module 50 is used to convert the direct current output by the DCDC module 40 into alternating current to feed back to the power grid 60, or convert the alternating current output by the power grid 60 into direct current to feed to other electrical equipment;

[0132] The control module 70 is used to obtain electrical parameters and compare them with preset threshold parameters, and adjust the operating state of the photovoltaic air conditioner according to the comparison result.

[0133] It should be noted that the photovoltaic air conditioning system further includes a filter module 120, which is located between the inverter module 50 and the power grid 60, and is used to remove or reduce noise and unnecessary frequency components in the signal. In addition, the DCDC module 40 proposed in this embodiment is provided with a plurality of bridge arms composed of IGBTs.

[0134] In this way, when the photovoltaic air-conditioning system switches from the pure photovoltaic mode to the grid-connected power generation mode, the current Iac on the AC side will decrease, and the control module 70 will compare the current Iac with the first current limit Imax1 and the first current limit Imax2; if Imax1≤Iac<Imax2, the control module 70 will maintain the current photovoltaic power, and will not keep the photovoltaic power output by the photovoltaic module 30 at the optimal power; if Iac<Imax1, the control module 70 will make the photovoltaic module 30 perform photovoltaic optimization to keep the photovoltaic power at the optimal power point, thereby making full use of the photovoltaic power generation energy of the photovoltaic module 30; and it can also avoid the situation where the photovoltaic power output by the photovoltaic module 30 is greater than the AC side power, thereby preventing the bus voltage from rising, and will not frequently trigger the bus overvoltage protection, thereby improving the stability and reliability of the operation of the photovoltaic air-conditioning system, and extending the service life of the bus capacitor and other corresponding electronic components.

[0135] If Iac≥Imax2, it indicates that the current on the AC side of the photovoltaic air-conditioning system will increase. Therefore, the control module 70 will reduce the photovoltaic power output by the photovoltaic module 30. During the reduction of the photovoltaic power output by the photovoltaic module 30, the control module 70 will continuously compare the current Iac with the first current limit Imax1 and the first current limit Imax2 until it is detected that Imax1≤Iac<Imax2. At this time, the control module 70 will maintain the current photovoltaic power and stop the photovoltaic optimization of the photovoltaic air-conditioning system.

[0136] When the photovoltaic air conditioning system does not need photovoltaic optimization, the control module 70 obtains the maximum power limit Ire of the photovoltaic power of the photovoltaic air conditioning system, and the maximum power limit Ire is not greater than the first current limit Imax1; determines whether the current Iac is greater than the maximum power limit Ire;

[0137] If so, the control module 70 determines that the photovoltaic air conditioning system performs photovoltaic optimization;

[0138] If not, the control module 70 determines that the photovoltaic air conditioning system again compares the current Iac, the first current limit value Imax1 and the first current limit value Imax2.

[0139] Among them, refer to the attached Figure 6 , the photovoltaic air conditioning system also includes:

[0140] An AC current sensor 80, wherein the AC current sensor 80 is connected in series between the inverter module 50 and the filter module 120;

[0141] The protection module 90 is connected to the AC current sensor 80 and the control module 70 respectively; the control module 70 can also be used to cut off the power supply of the photovoltaic air-conditioning system according to the output of the protection module 90, even if the entire photovoltaic air-conditioning system is powered off and stops running.

[0142] It should be noted that the AC current sensor 80 is used to obtain the real-time measurement value AD_Iac; the protection module 90 is preset with a first protection threshold value Iref1 and a second protection threshold value Iref2.

[0143] Specifically, refer to the attached Figure 7 , this embodiment proposes a circuit structure of the protection module 90:

[0144] The protection module 90 includes a comparator U1, a comparator U2, a resistor R1, a resistor R2 and a resistor R3;

[0145] The inverting end of the comparator U1 is used to connect to the Iref1 pin, and the Iref1 pin is used to input the first protection threshold value Iref1 to the comparator U1; the non-inverting end of the comparator U1 and the inverting end of the comparator U2 are respectively connected to the first end of the resistor R1, and the non-inverting end of the comparator U2 is used to connect to the Iref2 pin, and the Iref2 pin is used to input the second protection threshold value Iref2 to the comparator U2; the second end of the resistor R1 is connected to the output end of the AC current sensor 80;

[0146] The output end of the comparator U1 and the output end of the comparator U2 are connected to the first end of the resistor R2 and the first end of the resistor R3 respectively. The second end of the resistor R2 is used to connect to the 3.3V pin. The second end of the resistor R3 is connected to the input end of the control module 70.

[0147] In this way, this embodiment improves the hardware circuit protection of the photovoltaic air-conditioning system by adding a protection module 90. The protection module 90 receives the real-time measurement value AD_Iac output by the AC current sensor 80, and then compares the real-time measurement value AD_Iac, the first protection threshold value Iref1 and the second protection threshold value Iref2. If the real-time measurement value AD_Iac is not in the interval (Iref1, Iref2), the output end OCP of the protection module 90 will output a low level to the control module 70. After receiving the low-level signal, the control module 70 will trigger the overcurrent protection mechanism of the photovoltaic air-conditioning system, thereby cutting off the circuit of the entire photovoltaic air-conditioning system, making it completely power-off and stop running.

[0148] If AD_Iac is in the interval (Iref1, Iref2), the output terminal OCP of the protection module 90 will output a high level to the control module 70, and the control module 70 will maintain the current operating state of the photovoltaic air-conditioning system after receiving the high level signal.

[0149] Among them, refer to the attached Figure 6 , the photovoltaic air conditioning system also includes:

[0150] A DC current sensor 100 is connected in series between the photovoltaic module 30 and the DCDC module 40 ; the DC current sensor 100 is used to detect the current output by the photovoltaic module 30 .

[0151] The voltage sensor 110 is connected in parallel between the photovoltaic module 30 and the DCDC module 40 ; the voltage sensor 110 is used to detect the voltage output by the photovoltaic module 30 .

[0152] In this way, the control module 70 can obtain the output voltage and current of the photovoltaic module 30 flowing to the DCDC module 40 through the DC current sensor 100 and the voltage sensor 110, and then calculate the actual output power P of the photovoltaic module 30 according to the voltage and current, and then the control module 70 compares the actual output power P with the power limit reference value Plim; if P<Plim, the control module 70 determines that the photovoltaic air conditioning system continues to maintain photovoltaic optimization;

[0153] If P≥Plim, the control module 70 determines that the photovoltaic air conditioning system stops photovoltaic optimization and maintains the current photovoltaic power;

[0154] Then the control module 70 obtains and compares the current duty cycle Dt of the DCDC module 40 with the limited duty cycle reference value Dlim;

[0155] If D=Dlim, the control module 70 determines that the photovoltaic air conditioning system performs photovoltaic optimization;

[0156] If D≠Dlim, the control module 70 determines that the photovoltaic air-conditioning system continues to stop photovoltaic optimization and maintains the current photovoltaic power.

[0157] Obviously, the embodiments described above are only some embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are given in the accompanying drawings, but they do not limit the patent scope of the present invention. The present invention can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific embodiments, or to perform equivalent replacements for some of the technical features therein. Any equivalent structure made using the contents of the specification and drawings of the present invention, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present invention.

Claims

1. A photovoltaic air conditioner adaptive power regulation strategy, characterized in that: The adaptive power regulation strategy includes: Detect electrical parameters on the AC side of photovoltaic air conditioners; Comparing the electrical parameter with a preset threshold parameter, and determining the threshold interval in which the electrical parameter is located; The operating state of the photovoltaic air conditioner is adjusted according to the threshold range of the electrical parameter.

2. The photovoltaic air conditioner adaptive power regulation strategy according to claim 1 is characterized in that: The electrical parameter includes the current Iac, the threshold parameter includes a first current limit value Imax1 and a first current limit value Imax2, and the first current limit value Imax1 is less than the first current limit value Imax2, and the adaptive power regulation strategy includes: When Imax1≤Iac<Imax2, it is determined that the photovoltaic air conditioner maintains the current photovoltaic power; When Iac≥Imax2, it is determined that the photovoltaic air conditioner reduces the photovoltaic power; When Iac<Imax1, it is determined that the photovoltaic air conditioner performs photovoltaic optimization to keep the photovoltaic power at the optimal power point.

3. The photovoltaic air conditioner adaptive power regulation strategy according to claim 2 is characterized in that: When Iac≥Imax1, the adaptive power adjustment strategy includes: Acquire a maximum power limit value Ire of the photovoltaic power of the photovoltaic air conditioner, wherein the maximum power limit value Ire is not greater than the first current limit value Imax1; Determining whether the current Iac is greater than the maximum power limit Ire; If so, determining that the photovoltaic air conditioner performs photovoltaic optimization; If not, it is determined that the photovoltaic air conditioner again compares the current Iac, the first current limit value Imax1 and the first current limit value Imax2.

4. The photovoltaic air conditioner adaptive power regulation strategy according to claim 2 is characterized in that: When Iac<Imax1, the adaptive power adjustment strategy includes: Obtaining an actual output power P of the photovoltaic module of the photovoltaic air conditioner and a first voltage Um corresponding to a maximum output power Pmax; When the operating voltage U of the photovoltaic module is lower than the first voltage Um, the actual output power P is compared with a preset power limit reference value Plim of the photovoltaic module; If P≥Plim, it is determined that the photovoltaic air conditioner stops photovoltaic optimization and maintains the current photovoltaic power; If P<Plim, it is determined that the photovoltaic air conditioner continues to maintain photovoltaic optimization.

5. The photovoltaic air conditioner adaptive power regulation strategy according to claim 4 is characterized in that: When P≥Plim, the adaptive power regulation strategy includes: Obtaining a current duty cycle Dt and a limited duty cycle reference value Dlim of the photovoltaic air conditioner; Determine whether the current duty cycle Dt is equal to the limit duty cycle reference value Dlim; If so, determining that the photovoltaic air conditioner performs photovoltaic optimization; If not, it is determined that the photovoltaic air conditioner continues to stop photovoltaic optimization and maintains the current photovoltaic power.

6. The photovoltaic air conditioner adaptive power regulation strategy according to claim 5 is characterized in that: The calculation formula of the current duty cycle Dt is: Dt=ΔD+D(t-1); ΔD=K p ×e v +K i ×∫e v dt; e v =Vref-Vout; Among them, ΔD is the duty cycle disturbance step, D(t-1) is the duty cycle at the previous moment, K p is the proportional gain, K i is the integral gain, e v is the error signal, Vref is the preset voltage reference value of the bus, and Vout is the output voltage output to the bus.

7. The photovoltaic air conditioner adaptive power regulation strategy according to claim 1 is characterized in that: The adaptive power regulation strategy includes: Acquire a real-time measurement value AD_Iac, a first protection threshold value Iref1, and a second protection threshold value Iref2 output by the AC current sensor on the AC side; Determine whether the real-time measurement value AD_Iac is in the interval (Iref1, Iref2); If so, determining that the photovoltaic air conditioner keeps running; If not, it is determined that the photovoltaic air conditioner triggers a protection mechanism and the photovoltaic air conditioner is in a completely power-off state.

8. A photovoltaic air conditioning system, characterized in that: The photovoltaic air conditioning system comprises: A bus bar, on which a bus bar capacitor unit and an air conditioner are connected in parallel; Photovoltaic modules, which are used to convert solar energy into electrical energy; A DCDC module, the DCDC module is connected to the photovoltaic module; the DCDC module is used to convert the direct current output by the photovoltaic module into direct current suitable for use by other electrical equipment; An inverter module, the inverter module is connected to the DCDC module through a busbar, and the inverter module is also connected to the power grid; the inverter module is used to convert the direct current output by the DCDC module into alternating current to feed back to the power grid, or convert the alternating current output by the power grid into direct current to feed other electrical equipment; A control module is used to obtain electrical parameters and compare them with preset threshold parameters, and adjust the operating state of the photovoltaic air conditioner according to the comparison result.

9. The photovoltaic air conditioning system according to claim 8, characterized in that: The photovoltaic air conditioning system also includes: An AC current sensor is connected in series between the inverter module and the power grid; A protection module, wherein the protection module is connected to the AC current sensor and the control module respectively; the control module is also used to cut off the power supply of the photovoltaic air-conditioning system according to the output of the protection module.

10. The photovoltaic air conditioning system according to claim 8, characterized in that: The photovoltaic air conditioning system also includes: A direct current sensor connected in series between the photovoltaic module and the DCDC module; A voltage sensor is connected in parallel between the photovoltaic module and the DCDC module.

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